1. Field of the Invention
A callous is typically a buildup of a thickened outer layer of skin. Corns have an inner core which penetrates the epidermis. Both tend to develop from some irritant, and, while callouses are typically not painful, corns may well be painful and both conditions are unsightly and often uncomfortable.
Concern for corns, callouses and other skin buildups dates back to at least 2400 B.C., as evidenced by reliefs and other evidence found at, and in, the Tomb of the Physician in ancient Egypt. Hippocrates expressed the need for care of such problems in pre biblical times in Greece.
Today, skin care generally, and the removal of corns, callouses, and other unsightly skin buildups, has become a billion dollar business, according to the American Academy of Dermatology.
The number and type of products for removal of dead skin is voluminous, ranging from abrasives such as sandpaper, rasps and emery boards, which simply abrade the skin, to blade type devices such as razors, knives and scrapers, which are prominent in the art, and which actually cut away unwanted skin, to pierced metal devices.
In the pierced metal devices, holes are punched into a metal sheet, causing a series of raised, essentially conical, bumps, in which the continuous edge about the opening is the result of the tearing of the metal by the punch, but because of its macroscopic size, serves to remove unwanted skin by abrading or scraping it off.
There are also myriad, often perfumed, chemicals available to consumers, which chemically soften and dissolve such buildups of unwanted and unsightly skin.
All of these products, whether used for cosmetic or medical purposes, are susceptible to excesses which can result in damage to viable growing tissue.
2. Description of Related Art
At least some of the various forms of devices for the removal of unwanted skin have been patented, although many simply come to the market in neat and attractive packaging. One of the earlier patents related to the use of a blade for the trimming and removal of corns and callouses was issued to Jackson as U.S. Pat. No. 1,714,371. Jackson's device resembles the venerable safety razor and professes to eliminate deep cuts.
Several other blade type devices have achieved patent status, among them Potvin U.S. Pat. No. 2,612,683 in which the head is formed with a recess, which receives a flat blade used to trim away excess dead skin. Potvin also issued U.S. Pat. No. 2,573,487 in which the blade is recessed behind a head 4.
Other blade type callous removers include Pracht U.S. Pat. No. 3,636,625, and Gilhaus et. al U.S. Pat. No. 3,797,505.
The art is replete with sand papers and emery boards, all in common usage. Many are encased in an attractive and decorative handle, primarily for sales purposes. Others are powered, whether by battery or other electrical means.
At least one such file has been patented as a nail file, i.e., Haga U.S. Pat. No. 4,422,465. While not specifically designed as a device for removing excess skin, it nonetheless seemingly has that capacity, and it is formed by a photochemical etching process, although the process differs in significant ways from that employed by the present invention.